OFFSET
1,2
FORMULA
Equals the logarithmic derivative of A228648.
EXAMPLE
L.g.f.: L(x) = x + 5*x^2/2 + 31*x^3/3 + 453*x^4/4 + 14131*x^5/5 +...
where
exp(L(x)) = 1 + x + 3*x^2 + 13*x^3 + 128*x^4 + 2974*x^5 + 161048*x^6 + 19632276*x^7 +...+ A228648(n)*x^n +...
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 28 2013
STATUS
approved